Most multicellular organisms have a major body cavity containing vital organs. This cavity is lined by a mucosa-like serosal surface and filled with serous fluid which suspends many immune cells. Injuries affecting the major body cavity are potentially life-threatening. Here we summarize evidence that unique damage detection and repair mechanisms have evolved to ensure immediate and swift repair of injuries at serosal surfaces. Furthermore, thousands of patients undergo surgery within the abdominal and thoracic cavities each day. While these surgeries are potentially lifesaving, some patients will suffer complications due to inappropriate scar formation when wound healing at serosal surfaces defects. These scars called adhesions cause profound challenges for health care systems and patients. Therefore, reviewing the mechanisms of wound repair at serosal surfaces is of clinical importance. Serosal surfaces will be introduced with a short embryological and microanatomical perspective followed by a discussion of the mechanisms of damage recognition and initiation of sterile inflammation at serosal surfaces. Distinct immune cells populations are free floating within the coelomic (peritoneal) cavity and contribute towards damage recognition and initiation of wound repair. We will highlight the emerging role of resident cavity GATA6+ macrophages in repairing serosal injuries and compare serosal (mesothelial) injuries with injuries to the blood vessel walls. This allows to draw some parallels such as the critical role of the mesothelium in regulating fibrin deposition and how peritoneal macrophages can aggregate in a platelet-like fashion in response to sterile injury. Then, we discuss how serosal wound healing can go wrong, causing adhesions. The current pathogenetic understanding of and potential future therapeutic avenues against adhesions are discussed.

Introduction The COVID-19 (SARS-CoV-2) pandemic drove acute care surgeons to pivot from long established practice patterns. Early safety concerns regarding increased postoperative complication risk in those with active COVID infection promoted antibiotic-driven non-operative therapy for select conditions ahead of an evidence-base. Our study assesses whether active or recent SARS-CoV-2 positivity increases hospital length of stay (LOS) or postoperative complications following appendectomy. Methods Data were derived from the prospective multi-institutional observational SnapAppy cohort study. This preplanned data analysis assessed consecutive patients aged ≥ 15 years who underwent appendectomy for appendicitis (November 2020–May 2021). Patients were categorized based on SARS-CoV-2 seropositivity: no infection, active infection, and prior infection. Appendectomy method, LOS, and complications were abstracted. The association between SARS-CoV-2 seropositivity and complications was determined using Poisson regression, while the association with LOS was calculated using a quantile regression model. Results Appendectomy for acute appendicitis was performed in 4047 patients during the second and third European COVID waves. The majority were SARS-CoV-2 uninfected (3861, 95.4%), while 70 (1.7%) were acutely SARS-CoV-2 positive, and 116 (2.8%) reported prior SARS-CoV-2 infection. After confounder adjustment, there was no statistically significant association between SARS-CoV-2 seropositivity and LOS, any complication, or severe complications. Conclusion During sequential SARS-CoV-2 infection waves, neither active nor prior SARS-CoV-2 infection was associated with prolonged hospital LOS or postoperative complication. Despite early concerns regarding postoperative safety and outcome during active SARS-CoV-2 infection, no such association was noted for those with appendicitis who underwent operative management.

Background: Treatment of subdiaphragmatic collection by intercostal image-guided drain placement is associated with a risk of pleural complications including potentially life-threatening pleural empyema.Descriptions of patient characteristics and clinical course of postinterventional pleural empyema are lacking.We aim to present characteristics, clinical course and outcomes of patients with empyema after intercostal approach of drain placement.Methods: Data was collected as a retrospective single center case series and included adult patients with decortication for treatment of pleural empyema after image-guided percutaneous intercostal drainage of a subdiaphragmatic collection between 01.01.2009 and 31.01.2021. Results:We identified ten patients, nine male and one female, all suffering from subdiaphragmatic collection treated with intercostal drain. All patients developed pleural empyema after drain placement and received surgical decortication. Similarities between patients were drain placement under computed tomography (CT)-guidance (eight of ten patients), lateral position of the drain (seven of ten patients), drain insertion in the eighth intercostal space (ICS) (six of ten patients) and existing comorbidities as malnutrition (six of ten patients), diabetes (four of ten patients) and cancer (three of ten patients). The majority of patients had a prolonged length of hospital stay (LOS) with an average duration of 40 days. Nearly half of the patients needed intensive care unit (ICU) treatment and one patient died postoperatively from respiratory exhaustion.Conclusions: In this series, empyema after intercostal drainage was associated with prolonged LOS and was potentially life-threatening. The most commonly shared features in our cohort were the high prevalence of comorbidities, drain insertion above ninth ICS as well as lateral position of the drain. These factors should be addressed in prospective studies to evaluate potential correlation with postinterventional empyema. For optimal management of patients with subdiaphragmatic collection treated by intercostal drainage, awareness of potential associated complications is crucial.

Introduction Surgically managed appendicitis exhibits great heterogeneity in techniques for mesoappendix transection and appendix amputation from its base. It is unclear whether a particular surgical technique provides outcome benefit or reduces complications. Material and methods We undertook a pre-specified subgroup analysis of all patients who underwent laparoscopic appendectomy at index admission during SnapAppy (ClinicalTrials.gov Registration: NCT04365491). We collected routine, anonymized observational data regarding surgical technique, patient demographics and indices of disease severity, without change to clinical care pathway or usual surgeon preference. Outcome measures of interest were the incidence of complications, unplanned reoperation, readmission, admission to the ICU, death, hospital length of stay, and procedure duration. We used Poisson regression models with robust standard errors to calculate incident rate ratios (IRRs) and 95% confidence intervals (CIs). Results Three-thousand seven hundred sixty-eight consecutive adult patients, included from 71 centers in 14 countries, were followed up from date of admission for 90 days. The mesoappendix was divided hemostatically using electrocautery in 1564(69.4%) and an energy device in 688(30.5%). The appendix was amputated by division of its base between looped ligatures in 1379(37.0%), with a stapler in 1421(38.1%) and between clips in 929(24.9%). The technique for securely dividing the appendix at its base in acutely inflamed (AAST Grade 1) appendicitis was equally divided between division between looped ligatures, clips and stapled transection. However, the technique used differed in complicated appendicitis (AAST Grade 2 +) compared with uncomplicated (Grade 1), with a shift toward transection of the appendix base by stapler (58% vs. 38%; p < 0.001). While no statistical difference in outcomes could be detected between different techniques for division of appendix base, decreased risk of any [adjusted IRR (95% CI): 0.58 (0.41–0.82), p = 0.002] and severe [adjusted IRR (95% CI): 0.33 (0.11–0.96), p = 0.045] complications could be detected when using energy devices. Conclusions Safe mesoappendix transection and appendix resection are accomplished using heterogeneous techniques. Technique selection for both mesoappendix transection and appendix resection correlates with AAST grade. Higher grade led to more ultrasonic tissue transection and stapled appendix resection. Higher AAST appendicitis grade also correlated with infection-related complication occurrence. Despite the overall well-tolerated heterogeneity of approaches to acute appendicitis, increasing disease acuity or complexity appears to encourage homogeneity of intraoperative surgical technique toward advanced adjuncts.

Objective Male sex is controversially discussed as a risk factor for surgical site infections (SSI). The aim of the present study was to evaluate the impact of sex on SSI in abdominal surgery under elimination of relevant confounders. Methods Clinicopathological data of 6603 patients undergoing abdominal surgery from a multi-center prospective database of four Swiss hospitals including patients between 2015 and 2018 were assessed. Patients were stratified according to postoperative SSI and risk factors for SSI were identified using univariate and multivariate analysis. Results In 649 of 6603 patients, SSI was reported (9.8%). SSI was significantly associated with reoperation (22.7% vs. 3.4%, p < 0.001), increased mortality rate (4.6% vs. 0.9%, p < 0.001), and increased rate of length of hospital stay > 75th percentile (57.0% vs. 17.9%, p < 0.001). In univariate analysis, male sex was a significant risk factor for SSI (p = 0.01). In multivariate analysis including multiple confounders’ such as comorbidities and perioperative factors, there was no association between male sex and risk of SSI (odds ratio (OR) 1.1 [CI 0.8–1.4]). Independent risk factors for SSI in multivariate analysis were BMI ≥ 30 kg/m2 (OR 1.8 [CI 1.3–2.3]), duration of surgery > 75th percentile (OR 2.3 [1.8–2.9]), high contamination level (OR 1.3 [1.0–1.6]), laparotomy (OR 1.3 [1.0–1.7]), previous laparotomy (OR 1.4 [1.1–1.7]), blood transfusion (OR 1.7 [1.2–2.4]), cancer (OR 1.3 [1.0–1.8] and malnutrition (OR 2.5 [1.8–3.4]). Conclusion Under elimination of relevant confounders, there is no significant correlation between sex and risk of SSI after abdominal surgery.